GWEB 0.2.0

GWEB 0.2.0 brings Korean literate programming — and, found while writing the
first Korean example, a CWEB-conformance fix for section-name matching.

Korean documentation (new)

Put \input kotexgweb.tex in a .w file's limbo and typeset the woven output
with luatex (not pdftex) to get a fully Korean document — Hangul body,
running heads, contents page, section-name list, and cross-reference notes — with
blue cross-reference links and a Korean PDF outline (bookmark) pane.

• tex/kotexgweb.tex is one self-contained file: it loads luatexko, sets the
  Noto Serif/Sans CJK KR fonts, restates gweave's fixed wording in Korean, and
  supplies a LuaTeX PDF back end (gwebmac's links/bookmarks use pdfTeX
  primitives luatex lacks). PDF outline titles are emitted as UTF-16BE so Korean
  bookmarks render correctly.
• The running-head Hangul is set in a sans face to match the small-caps Latin,
  and the contents-page title is sized to match English gweb.
• Localization is language-agnostic: every fixed string gweave/gwebmac emit
  goes through a macro (\GU, \GNused, \Gsectionword, \Gheadfont, …), so
  another language needs only its own \input file. install.sh installs
  kotexgweb.tex next to gwebmac.tex.

Bug fix

• Section-name whitespace. As in CWEB, runs of spaces, tabs, and newlines in
  a section name are now collapsed to a single space and trimmed, so a long name
  wrapped across lines in one place matches the same name written on one line.
  Previously such a reference resolved to section 0 — which also crashed luatex's
  PDF backend.

Typesetting refinements (gweave / gwebmac)

• const and iota names are set in typewriter, like CWEB's @d macros; nil,
  true, false are typewriter (not bold); @d marks an imported name (e.g.
  http.StatusOK) as typewriter.
• Type names are set in boldface.
• A narrower, tunable thin space (\Gthin, 2mu) before (.
• TeX is passed through in section names (so \.{x} works), and @(file@>=
  output names are typeset as escaped typewriter paths (underscores, etc.).

New example programs

hangul.w (Korean Fibonacci), pipeline.w (lazy iter.Seq transforms bridged
to a channel fan-out), pairsums.w (max pair-product over subarrays via a Li
Chao tree), squint.w (McIlroy's lazy power series as channel networks),
topswops.w / topswops_fwd.w (Conway's game), and fast_cancel.w.

Tooling & docs

• gtangle -version / gweave -version report 0.2.0.
• .gitignore covers CWEB-style aux files (*.idx, *.scn).
• VS Code: control codes after leading whitespace are highlighted; VSIX install
  is recommended.
• README and manual updates.